It seems that Zoroastrianism is in danger of disappearing because no effort is made to spread the faith.Yet for it to have become the main religion of Persia some missionary work must have taken place. Have Zoroastrians given up trying to spread their faith and if so why?

Attempting to gain converts as a minority religion is very dangerous in most of the world, especially when the majority religion is Islam, which has rules against any attempt to convert Muslims. For their own protection, Zoroastrians gave up seeking converts many centuries ago, and now being closed to converts is a defining characteristic of the religion.

It's doubtful that proselytizing was ever a major practice of Zoroastrianism, however. The ancient Persian Empire seemed content to respect the religious cultures of everyone they conquered. This may have merely been wise politics, but it seems to be the way things were conducted.

It would be a terrible shame if Zoroastrianism was to disappear. It is one of the great religious traditions, ever.

While Islam is hostile to conversion attempts, the modern west is quite different. Perhaps, after so long, Zoroastrians should reconsider their non-proselytizing stance and seek converts in such places as that, amongst others.

Zoroastrianism, as I've heard it commented, is something one was born into...not converted into. Although Zarathustra used the practice during the seminal foundation of his "magusian" reform, proselytizing was often later looked upon as inherently corrupting. I'd say the sentiment has been born out countless times throughout the world.

Something I've found in my initial research into Zoroastrianism is that there is a visable divide between convert attitudes in the East and West. In the East, conversion into the faith is less accepted, much like the Hindu attitude in that one is born a Hindu or a Zoroastrian. In the West, Zoroastrians "accept" converts, much to the frustration of some Eastern "traditionalists." What is interesting here is that because traditionalists don't always recognize converts and are therefore dying out, we may be witnessing an evolution in the faith where where "permissive" Western Zoroastrians propogate the faith to a state of being mainstream while the old school exclusive ideology fades away.